1. Field of the Invention
This invention relates generally to cargo containers and their construction and, more particularly to the construction of lightweight cargo containers dimensioned to International Standards Organization (ISO) specifications. Although this invention finds particular utility in cargo containers intended for air transport, it is expressly to be understood that the advantages of the invention are equally manifest in other types and sizes of containers, wherever strength, low cost and reduced weight are desired.
2. Background of the Invention
Cargo is frequently shipped in bulk containers to reduce handling and expedite loading and unloading operations. To facilitate handling of these containers, various characteristics such as dimensions, strength requirements and fittings have been standardized under guidelines promulgated by the ISO. In order to comply with these guidelines, most containers of this type are constructed of steel or aluminum and are quite heavy. Joints are frequently welded or bolted and sealed, requiring substantial assembly time and adding weight. Because they are rather bulky and heavy, intital use of these containers has been limited to various means of land or sea transport. The introduction of wide-body aircraft has caused air shipment of ISO containers to be more seriously considered, however their weight continues to reduce aircraft payload to such an extent as to make their use economically impractical under most circumstances.
Prior attempts to produce a lightweight container capable of meeting ISO Standards have encountered numerous difficulties. Frequently these lightweight containers are unable to satisfactorily withstand the abuse of repeated loading and unloading. Container corner fittings of lightweight material frequently suffer handling damage requiring the container to be removed from service for extensive repairs. Prior lightweight containers require a complex assembly procedure which is both time consuming and costly.
It is, accordingly, an object of the invention to provide a lightweight cargo container that overcomes the disadvantages and limitations of the prior art.
It is another object of the invention to provide an easily manufactured fitting that permits secure attachment of container walls to each other.
It is yet another object of the invention to provide a lightweight cargo container that may be easily assembled.